Power steering system for adjustable track vehicles

ABSTRACT

A power steering system for adjustable track vehicles wherein a double-ended power cylinder moves a piston which carries a hollow power rod. The power rod in turn receives end portions of tie rod socket arms telescopically. The socket arms are attachable to the power rod at various points along the length of the socket arm to accommodate adjustability in the vehicle track. The socket arms terminate in movable stud joints which are connected to tie rod arms which in turn are connected to the wheel steering arm.

United States Patent [1 1 Herbenar Jan. 1,1974

[ POWER STEERING SYSTEM FOR ADJUSTABLE TRACK VEHICLES [75] Inventor:Edward J. Herbenar, Detroit, Mich.

[73] Assignee: TRW Inc., Cleveland, Ohio [22] Filed: Feb. 22, 1972 21Appl. No.: 227,770

[52] U.S. Cl ISO/79.2 R, ISO/DIG. 2, 280/34 R,

280/95 R [51] Int. Cl 862d 5/10, B62d 17/00 [58] Field of Search 180/792R, DIG. 2; 280/34 R, 95 R [56] References Cited UNITED STATES PATENTS1,806,136 5/1931 Weiss ISO/79.2 R X 3.527.316 9/1970 Jones et al7180/792 R 2,732,233 l/l956 MacMillan et al.... 280/95 R X 1,775,1769/1930 Stokes 180/792 R 3,137,360 6/1964 Biedess ISO/79.2 R X 2,911,2291 H1959 Strehlow 280/34 R X 3,229,992 l/l966 Traywick 280/95 R 3,035,8505/1962 Dyer 280/95 R Primary Examiner-Kenneth H. Betts AssistantExaminer-Leslie J. Paperner Attorney-Carlton Hill et a1.

[5 7] ABSTRACT A power steering system for adjustable track vehicleswherein a double-ended power cylinder moves a pis ton which carries ahollow power rod. The power rod in turn receives end portions of tie rodsocket arms telescopically. The socket arms are attachable to the powerrod at various points along the length of the socket arm to accommodateadjustability in the vehicle track. The socket arms terminate in movablestud joints which are connected to tie rod arms which in turn areconnected to the wheel steering arm.

3 Claims, 3 Drawing Figures POWER STEERING SYSTEM FOR ADJUSTABLE TRACKVEHICLES BACKGROUND OF THE INVENTION 1. Field of the Invention Thisinvention relates to steering linkages and more particularly to apower-assisted steering linkage for adjustable track vehicles.

2. Prior Art Adjustable track vehicles, such as four-wheel farmtractors, have to be equipped with steering linkage assembliesconnecting the dirigible wheels to the steering gear in a manner whichcan accommodate differences in the distance between the dirigiblewheels.

Farm tractors, especially those of the four-wheel type, have axleadjustments which allow the two front wheels to be spaced apart atvarying distances to allow the tractor to move through a planted fieldwith the wheels only in the spaces between the planted rows. Since rowspacing varies for numerous reasons, the tractors must be able to changethe positioning of the wheels.

In order to provide for steerability of the front wheels, while at thesame time accommodating adjustability of the wheels, it has been knownto provide steering linkages having adjustable length factors. A commonway of doing this has been to provide tie rods connected to a Pitmanarm, the tie rods being of adjustable length.

The advent of power-assisted steering in connection with adjustabletrack vehicles has complicated the steering linkage adjustabilityproblems. Because the tie rods must now be acted upon by a power member,they must either be attached to the power member in an adjustable manneror they must be designed to work with the power member while retainingtheir adjustability.

SUMMARY My invention provides a novel combination of power member andsteering linkage for use with adjustable track vehicles.

The invention utilizes a double-ended hydraulic power cylinder having acentrally disposed piston which is moved axially in the cylinderhydraulically. The piston is formed around and comprises part of ahollow power rod extending entirely through the cylinder and projectingbeyond the ends thereof in movable relationship with the cylinder. Thatis to say that the power rod is movable axially in the cylinder underthe influence of the movement of the piston.

Socket-ended steering rods have their opposite ends received in theinterior of the power rod through the open ends thereof. The rods have anumber of openings extending therethrough which are indexable with boltopenings adjacent the ends of the power rod. In this manner, the degreeof projection of the socket-ended rods into the ends of the power rod isadjustable.

The sockets on the ends of the socket rods carry movable stud jointswhich are attached to one end of the tie rod arms, the other end of thetie rod arms being attached to the steering arm of the dirigible wheel.The use of the tie rod arms allows for non-similarity of movementbetween the socket arms and the steering arms.

The sockets on the end of the socket arms are preferably attached in anadjustable manner so as to provide for toe adjustment of the dirigiblewheels, independent of the track adjustment.

It is therefore an object of this invention to provide a steeringlinkage for adjustable track vehicles.

It is an important object of this invention to provide a power-assistedsteering assembly for adjustable track vehicles.

It is another and specific object of this invention to provide anadjustable-width power assisted steering assembly for use in connectionwith adjustable track vehicles.

It is yet another and more specific object of this invention to providea power-assisted steering linkage assembly utilizing a double-endedhydraulic power cylinder which actuates a power rod having openings ateither end thereof into which are telescopically received linkagemembers adjustably positionable to varying depths of penetration.

It is a most specific object of this invention to provide apower-assisted steering linkage assembly for adjustable track vehicles,the assembly including a doubleended hydraulic cylinder which moves apower rod transverse of the vehicle, the power rod having open ends withlinkage members telescopically projecting into the open ends, the degreeof projection being variable, the linkage members terminating in socketswhich are attached to tie rod arms which in turn are attached tosteering arms whereby the linkage members may move only transversely ofthe vehicle while the steering arms move arcuately.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantagesof the invention will be readily apparent from the following descriptionof a preferred embodiment thereof, taken in conjunction with theaccompanying drawings, although variations and modifications may beeffected without departing from the spirit and and scope of the novelconcepts of the disclosure, and in which:

FIG. 1 is a perspective view of the dirigible wheels of an adjustabletrack vehicle equipped with the linkage assembly of this invention.

FIG. 2 is a partial cross-sectional view of the linkage assembly of FIG.1.

FIG. 3 is a view similar to FIG. 2, illustrating extensibility of thelinkage assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates the frontaxle l0 and dirigible wheels 11 and 12 of an adjustable track vehicle.The wheels ll and 12 are attached to wheel mount members 13 and 14 whichare received through openings in the ends of axle rods 15 and 16. Theaxle rods 15 and 16 extend into the ends 17 and 18 of an axle sleevemember 19. The axle sleeve member has bolts 20 projecting therethroughand through bores through the axle members 15 and 16 aligned with boltopenings 24. By removing the bolts 20 and moving the axle members 15 and16 to a different position within the sleeve and then re-inserting thebolts into aligned openings, it is possible to adjust the distancebetween the dirigible wheels 11 and 12 to the desired degree.

In order to allow the wheels 11 and 12 to be steered, they are mountedto the axle ends 15 and 16 in a rotatable manner, whereby rotation ofsteering ams 26 and 27 will turn the wheels.

My invention provides a power-assisted steering linkage for moving thesteering arms 26 and 27. The power-assisted steering linkage 30 includesa hydraulic power cylinder 31, a power-driven rod 32, socketendedsteering rods 33, and tie rod ends 34. In order to provide for thevarying widths between the wheels 11 and 12, the linkage of my inventionis adjustable as hereinafter described.

As best illustrated in FIG. 2, the power cylinder 31 includes acylindrical housing 40 having axial ends closed by end caps 41 and 42,defining an interior 43 which is open to the exterior by pressure ports44 and 45 opening through the cylinder housing 40 adjacent either endthereof and porting to the interior. The cylinder 31 is normallyattached to the frame of the vehicle in non-movable relation. Thepressure ports 44 and 45 are attached to a high-pressure source througha differentiating control operated in response to the steering wheel ofthe vehicle.

The end caps 41 and 42 have openings 46 and 47 therethrough protected byseals 48 surrounding a power rod 32,49 which extends entirely throughthe cylinder 40 projecting beyond the end caps 41 and 42. The power rodhas positioned therearound, centrally thereof, a seal or piston 50. Thepiston 50 is illustrated as being received around the power rod 49,however, it is to be understood that it can be a separate element towhich ends of two separate power rods are attached to form a singleunit. The piston is positioned interiorly of the cylinder 40, and isshiftable axially therein in the manner of a hydraulic piston. Thedifferentiating highpressure control operates to port pressure throughthe opening 44 or the opening 45 in varying degrees so as to move thepiston 50 axially of 'the cylinder to a desired position within thecylinder.

The power rod 49 is a hollow cylinder having a central opening 51extending form one end 52 to the other end 53 of the power rod. Sincethe power rod is attached to the seal or piston 50, it moves therewithaxially through the cylinder 40. Bolt holes 55 extend through the powerrod adjacent the ends 52 and 53. Linkage members or rods 47 and 58 aretelescopically received through the open ends 52-53 of the power rod.The linkage member rods 57-58 have a series of bores 59 extendingtherethrough, placed at varying spots along the length of the individualrods 57,58. Inasmuch as the rods 57-58 are telescopically received intothe power rod 49, the bores 59 can be indexed with the bolt openings 55and a bolt 60 projected therethrough. In this manner, the steeringlinkage is adjustable to any desired combined length. The bores 59 arepreferably spaced from one another approximately the same distance asthe corresponding bolt openings and bores of the axle 15,16 and axlesleeve 19 so that when the axle width is adjusted, the linkage can beadjusted to the same degree.

FIG. 3 illustrates the linkage as adjusted to its widest track. In thisinstance, the bolt 60 has been projected through the innermost 62 of thebores 59 on both the rods 57,58.

The rods 57,58 terminate, in the preferred embodiment, in ends whichhave openings 70 extending thereinto, the openings having femalethreads. The ends 72 and 73 are split as at 74, the split area beingsurrounded by a clamp 75. Ball joint sockets 76 have their male threadedstems 77 threaded into the female threaded openings 72,73.

The ball sockets 76 receive ball-ended studs 78 which project from thesocket 76 and which in turn are attached to tie rod ends 34, the otherends of which terminate in ball joints 79 which are attached to thesteering arms 26,27.

The termination of the rods 57,58 in ball joint sockets and the use ofthe tie rod ends 34 allows accommodation of the difference in movementsbetween the power rod 32 and the steering arms 26,27. Thus, when thehydraulic cylinder 31 is actuated to move the piston 50, the power rod32 moves axially of the cylinder. This movement is transferred to therotary movement of the steering arms through the tie rod ends 34 whichfunction in the manner of a drag linkage.

The attachment of the socket 76 by means of a threaded connection allowsadjustment of the length of the linkage from either side independent ofthe adjustability built into the attachment between the rods 57,58 andthe power rod. This allows the wheels to be ad justed for parallelism ortoe.

It can therefore be seen from the above that my invention provides apower-assisted steering linkage for use with adjustable track vehicles,the linkage having a power-moved member which telescopically receivessocket-ended members, the extent of telescopic projection of thesocket-ended members into the powermoved member being adjustable and thesocket-ended members being attached through tie rod ends to the steeringarm of the dirigible wheels of the vehicle. Ajustability of the wheelsis easily accomplished in the normal manner with the additional step ofremoving bolts attaching the socket-ended rods to the powerdriven rod toallow changes in the relative positioning of the tworods. Thereafter,after adjusting the track width of the vehicle, the bolts are,reinsertable to lock the rods to prevent further movement duringoperation of the linkage.

Although the teachings of my invention have herein been discussed withreference to specific theories and embodiments and although illustrativemeans for ac complishing explained results have been described, it is tobe understood that these are by way of illustration only and that othersmay wish to utilize my invention in different designs or applications.

I claim as my invention:

1. A vehicle having an axle extending transversely thereof, axle rods atboth ends of the axle in telescoped relation therewith, wheel mountingson the outer ends of the axle rods, wheels singably carried by saidmountings, steering arms on said mountings for swinging said wheels,means for adjusting the telescoped lengths of the axle and axle rods tovary the track width of the wheels, a double ended hydraulic powercylinder fixed transversely on the vehicle adjacent said axle, a pistonslidable in said cylinder, hollow piston shafts extending from thepiston through and beyond the ends of the cylinder, steering rodsslidably telescoped in the ends of the hollow piston shafts, tie rods atthe ends of the steering rods, ball joints on the ends of the tie rods,the joints at the inboard ends of the tie rods connected to the steeringrods in adjustable telescoped relation, the joints at the outboard endsof the tie rods connected to the steering arms, means locking the axlerods in selected telescoped relation with the axle to project the axlerods at selected distances beyond the axle, means locking the steeringrods in selected telescoped relation with the piston shafts to projectthe steering rods at distances accommodating the selected distances ofprojection of the axle rods, and means for adjustably connecting theball joints at the inboard ends of the tie rods in selected relationwith the steering rods to adjust the toe of the wheels without alteringthe projection of said steering rods.

2. The vehicle of claim 1 wherein the ball joints at the inboard ends ofthe tie rods have sockets with laterally projected stems threaded in theends of the steering rods and ball studs with shanks projecting from thesockets secured to the tie rods.

3. A power steering linkage for wheeled vehicles having adjustable trackwidths which comprises a doubleended hydraulic cylinder mountedtransversely of the power rod extending from both sides thereof throughboth ends of the cylinder, the outboard ends of said power rod beinghollow, steering rods slideably telescoped in said hollow outboard endsof the power rod, means for locking the steering rods to the power rodin selected telescoped relation with the power rod to project thesteering rods at selected distances beyond the power rod, tie rods atthe ends of the steering rods, tie rod joints connecting the tie rodswith the ends of the steering rods, and means for adjusting the jointsto vary the position of the inboard ends of the tie rods from theoutboard ends of the steering rods without altering the projection ofthe steering rods.

1. A vehicle having an axle extending transversely thereof, axle rods atboth ends of the axle in telescoped relation therewith, wheel mountingson the outer ends of the axle rods, wheels singably carried by saidmountings, steering arms on said mountings for swinging said wheels,means for adjusting the telescoped lengths of the axle and axle rods tovary the track width of the wheels, a double ended hydraulic powercylinder fixed transversely on the vehicle adjacent said axle, a pistonslidable in said cylinder, hollow piston shafts extending from thepiston through and beyond the ends of the cylinder, steering rodsslidably telescoped in the ends of the hollow piston shafts, tie rods atthe ends of the steering rods, ball joints on the ends of the tie rods,the joints at the inboard ends of the tie rods connected to the steeringrods in adjustable telescoped relation, the joints at the outboard endsof the tie rods connected to the steering arms, means locking the axlerods in selected telescoped relation with the axle to project the axlerods at selected distances beyond the axle, means locking the steeringrods in selected telescoped relation with the piston shafts to projectthe steering rods at distances accommodating the selected distances ofprojection of the axle rods, and means for adjustably connecting theball joints at the inboard ends of the tie rods in selected relationwith the steering rods to adjust the toe of the wheels without alteringthe projection of said steering rods.
 2. The vehicle of claim 1, whereinthe ball joints at the inboard ends of the tie rods have sockets withlaterally projected stems threaded in the ends of the steering rods andball studs with shanks projecting from the sockets secured to the tierods.
 3. A power steering linkage for wheeled vehicles having adjustabletrack widths which comprises a double-ended hydraulic cylinder mountedtransversely of the vehicle, a piston slidable in said cylinder having apower rod extending from both sides thereof through both ends of thecylinder, the outboard ends of said power rod being hollow, steeringrods slideably telescoped in said hollow outboard ends of the power rod,means for locking the steering rods to the power rod in selectedtelescoped relation with the power rod to project the steering rods atselected distances beyond the power rod, tie rods at the ends of thesteering rods, tie rod joints connecting the tie rods with the ends ofthe steering rods, and means for adjusting the joints to vary theposition of the inboard ends of the tie rods from the outboard ends ofthe steering rods without altering the projection of the steering rods.